drivers/leds/leds-syscon.c

Source file repositories/reference/linux-study-clean/drivers/leds/leds-syscon.c

File Facts

System
Linux kernel
Corpus path
drivers/leds/leds-syscon.c
Extension
.c
Size
3312 bytes
Lines
138
Domain
Driver Families
Bucket
drivers/leds
Inferred role
Driver Families: implementation source
Status
source implementation candidate

Why This File Exists

Repeatable hardware-adapter layer. Deep compatibility for every driver is out of scope; this atlas records patterns, probe lifecycles, bus glue, IRQ/DMA usage, and links back to core abstractions.

Dependency Surface

Detected Declarations

Annotated Snippet

struct syscon_led {
	struct led_classdev cdev;
	struct regmap *map;
	u32 offset;
	u32 mask;
	bool state;
};

static void syscon_led_set(struct led_classdev *led_cdev,
	enum led_brightness value)
{
	struct syscon_led *sled =
		container_of(led_cdev, struct syscon_led, cdev);
	u32 val;
	int ret;

	if (value == LED_OFF) {
		val = 0;
		sled->state = false;
	} else {
		val = sled->mask;
		sled->state = true;
	}

	ret = regmap_update_bits(sled->map, sled->offset, sled->mask, val);
	if (ret < 0)
		dev_err(sled->cdev.dev, "error updating LED status\n");
}

static int syscon_led_probe(struct platform_device *pdev)
{
	struct led_init_data init_data = {};
	struct device *dev = &pdev->dev;
	struct device_node *np = dev_of_node(dev);
	struct device *parent;
	struct regmap *map;
	struct syscon_led *sled;
	enum led_default_state state;
	u32 value;
	int ret;

	parent = dev->parent;
	if (!parent) {
		dev_err(dev, "no parent for syscon LED\n");
		return -ENODEV;
	}
	map = syscon_node_to_regmap(dev_of_node(parent));
	if (IS_ERR(map)) {
		dev_err(dev, "no regmap for syscon LED parent\n");
		return PTR_ERR(map);
	}

	sled = devm_kzalloc(dev, sizeof(*sled), GFP_KERNEL);
	if (!sled)
		return -ENOMEM;

	sled->map = map;

	if (of_property_read_u32(np, "reg", &sled->offset) &&
	    of_property_read_u32(np, "offset", &sled->offset))
		return -EINVAL;
	if (of_property_read_u32(np, "mask", &sled->mask))
		return -EINVAL;

	init_data.fwnode = of_fwnode_handle(np);

	state = led_init_default_state_get(init_data.fwnode);
	switch (state) {
	case LEDS_DEFSTATE_ON:
		ret = regmap_update_bits(map, sled->offset, sled->mask, sled->mask);
		if (ret < 0)
			return ret;
		sled->state = true;
		break;
	case LEDS_DEFSTATE_KEEP:
		ret = regmap_read(map, sled->offset, &value);
		if (ret < 0)
			return ret;
		sled->state = !!(value & sled->mask);
		break;
	default:
		ret = regmap_update_bits(map, sled->offset, sled->mask, 0);
		if (ret < 0)
			return ret;
		sled->state = false;
	}
	sled->cdev.brightness_set = syscon_led_set;

	ret = devm_led_classdev_register_ext(dev, &sled->cdev, &init_data);
	if (ret < 0)

Annotation

Implementation Notes